fix #3307: regression with tsconfig baseURL

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+* Fix a regression with `baseURL` in `tsconfig.json` ([#3307](https://github.com/evanw/esbuild/issues/3307))
+
+    The previous release moved `tsconfig.json` path resolution before `--packages=external` checks to allow the [`paths` field](https://www.typescriptlang.org/tsconfig#paths) in `tsconfig.json` to avoid a package being marked as external. However, that reordering accidentally broke the behavior of the `baseURL` field from `tsconfig.json`. This release moves these path resolution rules around again in an attempt to allow both of these cases to work.
+
 * Parse TypeScript type arguments for JavaScript decorators ([#3308](https://github.com/evanw/esbuild/issues/3308))
 
     When parsing JavaScript decorators in TypeScript (i.e. with `experimentalDecorators` disabled), esbuild previously didn't parse type arguments. Type arguments will now be parsed starting with this release. For example:

internal/bundler_tests/bundler_tsconfig_test.go

@@ -2511,3 +2511,30 @@ func TestTsconfigJsonTopLevelMistakeWarning(t *testing.T) {
 `,
 	})
 }
+
+// https://github.com/evanw/esbuild/issues/3307
+func TestTsconfigJsonBaseUrlIssue3307(t *testing.T) {
+	tsconfig_suite.expectBundled(t, bundled{
+		files: map[string]string{
+			"/Users/user/project/src/tsconfig.json": `
+				{
+					"compilerOptions": {
+						"baseUrl": "./subdir"
+					}
+				}
+			`,
+			"/Users/user/project/src/test.ts": `
+				export const foo = "well, this is correct...";
+			`,
+			"/Users/user/project/src/subdir/test.ts": `
+				export const foo = "WRONG";
+			`,
+		},
+		entryPaths:    []string{"test.ts"},
+		absWorkingDir: "/Users/user/project/src",
+		options: config.Options{
+			Mode:          config.ModeBundle,
+			AbsOutputFile: "/Users/user/project/out.js",
+		},
+	})
+}

internal/bundler_tests/snapshots/snapshots_tsconfig.txt

@@ -222,6 +222,15 @@ var require_util = __commonJS({
 var import_util = __toESM(require_util());
 console.log((0, import_util.default)());
 
+================================================================================
+TestTsconfigJsonBaseUrlIssue3307
+---------- /Users/user/project/out.js ----------
+// test.ts
+var foo = "well, this is correct...";
+export {
+  foo
+};
+
 ================================================================================
 TestTsconfigJsonCommentAllowed
 ---------- /Users/user/project/out.js ----------

internal/resolver/resolver.go

@@ -1000,20 +1000,9 @@ func (r resolverQuery) resolveWithoutSymlinks(sourceDir string, sourceDirInfo *d
 
 	// First, check path overrides from the nearest enclosing TypeScript "tsconfig.json" file
 	if sourceDirInfo != nil {
-		if tsConfigJSON := r.tsConfigForDir(sourceDirInfo); tsConfigJSON != nil {
-			// Try path substitutions first
-			if tsConfigJSON.Paths != nil {
-				if absolute, ok, diffCase := r.matchTSConfigPaths(tsConfigJSON, importPath); ok {
-					return &ResolveResult{PathPair: absolute, DifferentCase: diffCase}
-				}
-			}
-
-			// Try looking up the path relative to the base URL
-			if tsConfigJSON.BaseURL != nil {
-				basePath := r.fs.Join(*tsConfigJSON.BaseURL, importPath)
-				if absolute, ok, diffCase := r.loadAsFileOrDirectory(basePath); ok {
-					return &ResolveResult{PathPair: absolute, DifferentCase: diffCase}
-				}
+		if tsConfigJSON := r.tsConfigForDir(sourceDirInfo); tsConfigJSON != nil && tsConfigJSON.Paths != nil {
+			if absolute, ok, diffCase := r.matchTSConfigPaths(tsConfigJSON, importPath); ok {
+				return &ResolveResult{PathPair: absolute, DifferentCase: diffCase}
 			}
 		}
 	}
@@ -2318,6 +2307,14 @@ func (r resolverQuery) loadNodeModules(importPath string, dirInfo *dirInfo, forb
 		defer r.debugLogs.decreaseIndent()
 	}
 
+	// Try looking up the path relative to the base URL from "tsconfig.json"
+	if tsConfigJSON := r.tsConfigForDir(dirInfo); tsConfigJSON != nil && tsConfigJSON.BaseURL != nil {
+		basePath := r.fs.Join(*tsConfigJSON.BaseURL, importPath)
+		if absolute, ok, diffCase := r.loadAsFileOrDirectory(basePath); ok {
+			return absolute, true, diffCase
+		}
+	}
+
 	// Find the parent directory with the "package.json" file
 	dirInfoPackageJSON := dirInfo
 	for dirInfoPackageJSON != nil && dirInfoPackageJSON.packageJSON == nil {